A number of patents have been granted on structures and methods for creating waves in an enclosed body of water such as a pool. The Schuster and Boes in U.S. Pat. No. 3,629,877, issued Dec. 28, 1971, is one which created small, mostly up and down, waves in a pool, e.g., two to three-foot high waves, so that swimmers could enjoy being bounced around on such waves, such as when floating on a small raft. A number of other patents have been suggested for generating this type of wave for amusement purposes, such as U.S. Pat. No. 3,789,612 to Richard, which used a plunger being raised and lowered. The U.S. Pat. No. 4,276,661 to Baker utilized vertically reciprocating air cushion pistons to create waves. In U.S. Pat. No. 3,005,207, the inventor Matrai suggested a gate effect swinging around a vertical pivot while under water to create such waves. In U.S. Pat. No. 3,350,724, Leigh suggested a vertically reciprocating plunger.
U.S. Pat. No. 586,983 to Wharton referred to a breaking wave, but this breaking was only after the wave reached the shore and the wave was created by a horizontally reciprocating plunger, which occupied most of the pool. A similar effect was found in U.S. Pat. No. 586,718 to Wharton, wherein he states long waves are created and are converted into breakers by the return water flowing down the inclined beach. In this case, the long waves were created by water flowing from an overhead tank. U.S. Pat. No. 2,056,855 to Herz also showed similar types of waves in a swimming pool, presumably created by alternate suction and air pressure on caissons at one end of the pool. U.S. Pat. No. 3,557,559 to Barr, showed a reciprocating plunger which moved horizontally.
Only one installation of a pool with a shoreline and a machine to create actual breaking and surfing waves is known in the United States. By a breaking surfing wave is meant one which is high enough, e.g., five or six feet in elevation, so that one may use surfboards or may body surf on the forward-breaking portion of this surfing wave. A continuous wave front is created entirely across the width of the pool and traverses the length of the pool so that persons may ride a surfboard on the wave front the length of the pool. U.S. Pat. No. 3,473,334 to Phillip Dexter shows the initial concept of this pool later constructed. Such patent contemplates the formation of a surfing wave which actually curls over or breaks on the forward edge as it moves forward along the length of the pool, as distinguished from merely breaking on the shore, as shown in the Wharton patents. In the surfing wave pool actually constructed, the construction was not as shown in the U.S. Pat. No. 3,473,334 because the vertically moving gate was found to be impractical, but instead an arcuately moving gate was used, carried on a generally horizontal beam to a pivot point considerably upstream from the gate and within the enlarged reservoir. Also, the hydraulic cylinders to swing this beam and gate were always positioned in the water in this enlarged reservoir.
Such prior surfing wave pool assembly had a number of disadvantages, including a hydraulic system which was located on a floor above the water storage tank wherein it was not easily accessible for service, and also hydraulic oil could be spilled and run into the pool water. The arcuately swung gate valves were heavy and hard to operate easily, requiring hydraulic instead of pneumatic actuators with excessive maintenance. The pool had a sand bottom which was a continuous source of maintenance. Each hydraulic operator for the gate valve operation was located in the chlorinated water at all times, including nighttime, when the pool was not in operation for swimmers. The maintenance and service on these hydraulic cylinders was very costly and timeconsuming. In order to replace a hydraulic cylinder, it was necessary to drain the pool and the stored water and it took four days to refill the pool. If this happened during the operating season, there could be a serious loss of financial revenue.